PB97-963160
EPA/541/R-97/190
January 1998
EPA Superfund
Explanation of Significant Difference
for the Record of Decision:
Ford Ord, OU 2
Marina, CA
1/17/1997
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EXPLANATION OP SIGNIFICANT DIFFERENCES
CONSOLIDATION OF REMEDIATION WASTE IN A CORRECTIVE ACTION
MANAGEMENT UNIT (CAMU), OPERABLE UNIT 2 LANDFILL
FORT ORD, CALIFORNIA
United States Department of the Army
January 13, 1997
INTRODUCTION
Sit* Nam* and Location
Fort Ord is located near Monterey Bay in
northwestern Monterey County, California,
approximately 80 miles south of San Francisco.
The base comprises approximately 28,000 acres
adjacent to the cities of Seaside, Sand City,
Monterey, and Del Key Oaks to the south and
Marina to the north. The Southern Pacific
Railroad and Highway 1 pass through the
western portion of Fort Ord, separating the
beachfront from the rest of the base. Laguna
Seca Recreation Area and Toro Regional Park
border Fort Ord to the south and southeast,
respectively. Land use east of Fort Ord is
primarily agricultural. Operable Unit 2 (OU 2),
the Fort Ord Landfills, comprises
approximately 150 acres in the northern
portion of Fort Ord.
The OU 2 landfills are in the northwesfportion
of Fort Ord (Figure 1). A playing field and
roads are located on the landfill north of Imjin
Road. The north landfill, known as Area A,
covers approximately 30 acres, and is separated
from the main landfill to the south by Imjin
Road. Area A is the only portion of the landfill
that is developed and near houses. The main
landfill encompasses about 120 acres of
undeveloped land.
Identification of Load and Support
Agendas
Environmental investigations began at Fort Ord
in 1984 at Fritzsche Army Airfield (FAAF)
under California Regional Water Quality
Control Board (RWQCB) cleanup or abatement
orders 84-92, 86-86, and 86-135. In 1986,
further investigations began at the OU 2
Landfills, and the preliminary site
characterization was completed in 1988. In
1990, Fort Ord was placed on the U.S. EPA's
National Priorities List (NPL), primarily because
of volatile organic compounds (VOCs) found in
groundwater beneath OU 2. A Federal Facility
Agreement (FFA) was signed by the Army as
the lead agency, and the EPA, the California
Environmental Protection Agency's Department
of Toxic Substances Control (DTSC; formerly
the Toxic Substances Control Program of
Department of Health Services or DHS) and
RWQCB as support agencies.
Explanation of Significant Differences
If the lead agency (the Army) determines that a
significant change to the selected remedy, as
described in the Record of Decision (ROD), is
necessary after the ROD is signed,
Section 117{c) of the Comprehensive
Environmental Response, Compensation and
Liability Act (CERCLA) and 40 CFR 300.435
(c)(2)(i) require the lead agency to address
post-ROD significant changes.
Two previous Explanation of Significant
Differences (ESD) documents to the OU2 ROD
addressed: (1) groundwater cleanup goals for
the Upper 180-foot aquifer beneath the landfill,
and (2) preliminary remediation goals for
excavation areas in the landfill, and excavation
and consolidation of refuse from Area A into
the main landfill (August, 1995, August 1996).
This explanation of significant differences
(ESD) addresses soil and debris (remediation
waste) that will be excavated from remediation
areas at Fort Ord and consolidated within the
main landfill boundaries. The remediation
waste will be used as foundation layer material
in lieu of "clean" (uncontaminated) soil as
described in the OU2 ROD. The regulatory
agencies agree with the changes proposed in
this ESD. When the OU 2 ROD was prepared.
placing an engineered cover system, or cap,
over the landfill was planned, and clean soil
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was intended for use in construction of the
cap's foundation layer. Subsequent evaluations
indicated that foundation layer material could
be provided from excavation of remediation
areas instead of procuring clean soil.
Additionally, to allow excavated soil containing
residual lead contamination to be placed in the
OU 2 landfill, the landfill will be designated a
Corrective Action Management Unit pursuant
to California Code of Regulations and the
Resource Conservation and Recovery Act
(RCRA) regulations. Consolidation of waste in
the landfill meets the intent and purpose of the
Corrective Action Management Unit regulations
for onsite management of waste in an
innovative, cost effective and protective
manner. The Army will be managing all wastes
onsite in a closed landfill which will meet all
regulatory requirements and will be protective
of human health and the environment.
Furthermore, significant cost savings will be
realized by placing the waste in the landfill as
foundation layer material because: (1) the
volumes of imported soil required for the
foundation layer will be reduced, and
(2) transportation and disposal costs for offsite
disposal will be eliminated.
The BSD will become part of the Administrative
Record for Fort Ord, and will be available to the
public at the following locations: Chamberlain
Library, Building 4275, North-South Road,
Presidio of Monterey Annex (formerly.
Fort Ord), California, and Seaside Branch
Library, 550 Harcourt Avenue, Seaside,
California.
SUMMARY OF SITE HISTORY,
CONTAMINATION PROBLEMS, AND
SELECTED REMEDY
Site History
From its opening in 1917, Fort Ord primarily
served as a training and staging facility for
infantry troops. In 1991, Fort Ord was selected
for closure. In 1993, the majority of the
soldiers were reassigned to other Army posts.
The post was officially closed in 1994.
OU 2 comprises two adjacent landfill areas.
Both were used for residential and commercial
waste disposal. The north landfill (Area A) was
used from 1956 to 1966. The main landfill was
operated from 1960 to 1987 and may have
received a small amount of chemical waste
along with household and commercial refuse.
The main landfill facility stopped accepting
waste for disposal in May 1987 because interim
closure of the facility began.
SH« Characteristics
The results of the remedial investigation (RI) at
the OU 2 Landfills indicate that landfill
materials were buried in relatively uniform
sand dune deposits in shallow trenches that
were approximately 30 feet wide and 10 to
12 feet deep. Chemicals associated with
landfilled materials have been detected in
vapor samples from soil overlying the landfills
and in groundwater samples collected from
underneath the landfills. The chemicals are
believed to have migrated away from the
landfilled materials as vapors or as solutes in
leachate. However, soil samples collected
below the landfills did not contain chemicals
associated with the landfills.
SsJscted
The ROD for OU 2 was signed on August 23,
1994, and included the following remedy for
soil:
• A cover system for the landfills was
selected to prevent rainwater from
percolating through the landfilled areas
and into the underlying drinking water
aquifers, to contain and collect and
remove methane off gas (if necessary),
and to prevent sanitary waste in the
landfills from exposure to the
surrounding environment. The cover
system specifications are driven by
applicable or relevant and appropriate
requirements (ARARs) for landfill
closure. Institutional controls (i.e.,
deed restrictions and cap maintenance)
will be placed on the property to
protect people from exposure to
materials in the landfills in the future.
DESCRIPTION AND BASIS OP
SIGNIFICANT DIFFERENCES
Waste from remediation sites (such as Sites 3, 12,
16 and 17, 31. and 39) will be excavated and
placed in the OU 2 landfill. The existing landfill
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contains primarily household and commercial
waste from previous base activities. Waste from
most remediation sites contains soil and debris
which can be placed under the landfill cap
without any additional restrictions. The waste
consolidation will incorporate approximately
157,000 cubic yards of material from Remedial
Investigation sites as described in the Proposed
Plans for these sites (May 3,1996). and
e.OOOtcubic yards from Interim Action sites will
be incorporated into the OU 2 landfill to be used
as a foundation layer. The consolidated waste will
account for approximately 6% of the total landfill
volume.
Waste from Site 3, 31, and portions of Site 39, and
some Interim Action sites is of a different nature
from the other sites, primarily due to the presence
of spent ammunition (bullets) from small arms
target practice exercises at these sites and pesticide
contamination at one Interim Action site, in
addition, incinerated metal debris containing lead
was previously deposited at Site 31. Because of
the contaminant concentrations in soil at these
sites, these wastes are considered hazardous
wastes.
In order to place hazardous waste from
remediation sites in the landfill, Corrective Action
Management Unit (CAMU) regulations must be
followed. Placement of hazardous waste from the
remediation sites in the landfill will constitute
approximately 3% of the total volume of the
landfill. The Army and regulatory agencies
evaluated the compatibility and leacmng potential
of wastes from the various remediation sites in the
subsurface landfill environment at OU 2 in the
Technical Memorandum RI and IA Sites' Waste
Compatibility and Leaching Potential, January
1997. Results of the evaluation indicate that
wastes from these sites can be placed in the
landfill and will not react with the cap material or
other wastes within the landfill. Furthermore,
compounds present in the waste are not
anticipated to leach to groundwater when placed
in the landfill. After these wastes are placed in the
landfill, the cap will be installed and no additional
waste will be accepted. The cap will be inspected
and maintained by the Army in perpetuity and
groundwater will be monitored at regular intervals.
CAMU Regulations and Their Application to the
OU 2 Landfill
As defined in California Code of Regulations
(CCR), Title 22 Section 66264.552, a CAMU is an
area within a facility designated for purposes of
carrying out corrective action requirements under
CCR Title 22 and RCRA Section^308(h). In
general, the CAMU regulations were developed to
give regulatory agencies flexibility in selecting and
implementing the most effective and appropriate
waste management strategies for the cleanup of
large, complex sites such as Fort Ord. Fort Ord is
a large facility with numerous remediation sites
and an pxisHng landfill that requires fill material
for closure. The Army and the regulatory agencies
have designated the OU 2 landfill as a CAMU
(Figure 2). The following seven decision criteria
were evaluated to assess the viability to place
remediation waste from cleanup activities at
Fort Ord in the OU 2 landfill following CAMU
regulations.
The seven evaluation criteria include:
(1) The CAMU must facilitate the implementation
of reliable, effective, protective, and cost
effective corrective action measures.
• Foundation layer material (fill) is required
to construct the cover system, and waste
from remediation sites at Fort Ord is
suitable fill material, nUminating the need
for imported fill material and reducing
associated truck traffic, fuel consumption,
and air emissions.
(2) Waste management activities associated with
the CAMU shall not create unacceptable risks
to humans or the environment.
Remediation wastes will be placed
beneath an engineered landfill cover at the
OU 2 landfill, which includes a barrier
layer that protects humans and the
environment from contact with waste. In
addition, transport of wastes will be
limited to Fort Ord, thereby timiring
potential risks associated with offsite
disposal.
(3) The CAMU shall incorporate uncontaminated
areas only if the inclusion of such areas allows
better protection.
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The remediation waste will be placed
within the present boundaries of the OU 2
landfill; therefore, no uncontaminated area
will be impacted.
(4) Areas within the CAMU. where wastes remain
in place after closure of the CAMU, shall be
managed and contained so as to mtnimi«p the
potential for future releases.
The cap will be maintained to minimize
potential future releases, and long-term
monitoring of the landfill is required.
(5) The CAMU shall expedite the implementation
of corrective action measures.
Corrective action measures are expedited
since less time will be required to
transport waste to the existing OU 2
landfill than would be required to treat or
dispose offsite.
(6) The CAMU shall enable the use of treatment
technologies to enhance long term
effectiveness of corrective actions by reducing
the toxicity, mobility, or volume of wastes.
Leaching of waste components into
groundwater, and mobility of the material
will be minimized by installation of the
cap. In addition, the volume of waste will
be reduced by separation and recycling of
spent ammunition. *»
(7) To the extent practicable, the CAMU shall
minimize the land areas where wastes will
remain in place after closure of the CAMU.
• The remediation waste will be placed
within the present boundaries of the OU 2
landfill.
In summary, placement of remediation wastes
at the OU 2 landfill meets the evaluation
criteria outlined for designation of a CAMU.
CAMU regulations applicable to Fort Ord were
presented in the January 1997 Technical
Memorandum. This document is part of the
Administrative Record. The Administrative
Record is available for review by the public at
the following locations: Chamberlain Library,
Building 4275. North-South Road, Presidio of
Monterey Annex (formerly Fort Ord),
California, and Seaside Branch Library,
550 Harcourt Avenue, Seaside, California.
AFFIRMATION OF STATUTORY
DETERMINATIONS
This final remedy satisfies the requirements of
CERCLA Section 121. Consolidation of
remediation waste into the main landfill
required that CAMU criteria be evaluated and
the OU2 Landfill designated as a CAMU under
thisESD. The Army, U.S. EPA, and Cal/EPA
believe that this approach remains protective of
human health and the environment, complies
with federal and state ARARs for this remedial
action, and is able to be achieved in a cost
effective manner.
PUBLIC PARTICIPATION
A notification to the public concerning this BSD
will be made in a local newspaper after
signature. A public meeting concerning this
BSD and consolidation of remediation waste in
the CAMU was held on October 29,1996, and
public comments were accepted from October 8
through November 8,1996. The
Administrative Record is available for review
by the public at the following locations:
Chamberlain Library, Building 4275, North-
South Road, Presidio of Monterey Annex
(formerly Fort Ord), California, and Seaside
Branch Library, 550 Harcourt Avenue, Seaside,
California.
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Janutry 13.1997/33973-0072
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United States Department of the Army
~
/2.. ~~cr~
Date
Daniel D. Devlin
Colonel. U.S. Army
Commander
G~
BRAC Environmental Coordinator
Presidio of Monterey
3/o/q9-
Date
U.s. Environmental Protection Agency
d/d~' t/t7A7
D 'elO alski '/ Dat6
8~(Z.ederal Facilities Cleanup Branch
U.S. Environmental Protection Agency,
Region IX
JC47279-F .
January 13. 1997/33973-0072
CalHomla Environmental Protection
Agency
t2~~. ~ /-/\-q7
Anthony J. Landis, P.E. . Date
Chief of Operations
Office of Military Facilities California
Environmental Protection Agency
Department of Toxic Substances Control
tfrJchr
Roger W. Briggs
Executive Officer
California Environmental Protection.Agency
Central Coast Regional Water Quality
Control Board
'-?-'7
Date
50'5
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Figure!.
Fort Ord Location Map
Operable Unit 2 Landfill
Fort Ord, California
33B73 earn
110TB6DJP
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Figure 2. Site Map
Operable Unit 2 Landfill
Fort Ord, California
FORTORD if *x
BOUNDARY/
CITY OF
MARINA
Area of CAMU
Designation
iitttMtiittitiii
IIIIMMIMMini
uttttmntttiM
Operable
Unit 2
Landfill
APPROXIMATE
INTER GARRISON ROM SCALE IN FEET
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